Does having the s4 wheel liner on the passenger side help anything?

It can't hurt- maybe move a little air out from the turbo.

I disagree.
 

I have Turbo5's cone intake. Using VW Tool I did find an improvement of intake temperature by about 3 degrees or so after the installation of the liner. Granted 3 degrees is not that much, but it definitively did not hurt!

I also have the cone intake, and a passenger side S4 liner, but I'm starting to wirry about water...
 

and debris coming in and making contact with the cone filter. Is this is a real concern I should have? Or is there no way. The other day, I went through this HUGE puddle of water that had formed on the road, and I just winced at the thought of the cone filter getting soaked!

Pretty much yes.

maybe?
 

Raj,

I saw your other note on this and have an opinion, however as I am using neither the S4 wheel well liner nor a cone filter setup, I cannot speak from any experience.

My opinion after having things apart to do the "Europeanspeed Stage II air box mod" and having the chance to look at this area for the first time is that the only chance of throwing water up to the airbox with the S4 vented liner is when going thru deep water fairly slowly. This is because unlike what happens to water coming off the tire when driving on normal wet surfaces or fast, the vents in the S4 liner are wide open to water splashed up directly off the road by the front of the tire and this is likely to be a bigger problem at lower speeds and a couple inches or more of water. The type of speed and puddle that tosses water up above the hood line in front of the car is what I am thinking about.

Since you have a cone filter setup maybe you can look to see if there is a more or less direct path from the ground immediately in front of the tire to the filter element. If there is then you do have some risk that splash in puddles will reach the filter directly.

Another way to tell is to look for dried telltale waterspots from a previous trip thru a puddle or to make it a point of stopping right after going thru a couple to look for water droplets near or on the filter.

hmmm, you're right, I think. I was trying to justify the same point about water trajectories myself,
 

but wasn't sure. Since you're also saying this, I guess it's true. In any case, I'll get in there and check for water stains. Thanks!